The relationship between legal realism and legal positivism has been a constant source of debate since the emergence of realist theories in the first half of the 20th century. The discussion has been further complicated by the related difficulty of assessing the internal relationship between the two main strands of realism: American and Scandinavian.

More is at stake in this debate than taxonomic neatness; at stake are wide‐reaching methodological questions as to what kind of a science the study of law should be according to legal realism, questions that are often formulated in a modern context as questions about the potential for naturalism in legal science.

Much confusion seems to stem from a failure to correctly identify the kind of rule‐skepticism underlying realism or from the related failure to correctly identify possible differences on this issue between the two kinds of realism. With specific regard to American realism recent work, notably by Brian Leiter, has admittedly been helpful in correcting some of these misunderstandings. But with regard to Scandinavian realism we do not seem to be much farther along today than where Hart left us half a century ago with his hugely influential but equally mistaken writings on legal realism.

In this paper I suggest bringing discussion forward by introducing a distinction between two kinds of rule‐skepticism, i.e. between so‐called forward-looking rule‐skepticism which is implicational and decisional and backward-looking rule‐skepticism which is regressive and foundational. I then argue that we ought to see American and Scandinavian realism as being based respectively on forward‐looking and backward‐looking rule‐skepticism. This gives us a clearer understanding not only of the fundamentally different kinds of theoretical relationship between each of the two realisms and legal positivism but also of the equally different prospects of naturalism delivered by each of them.